拍照或者图库选择的图片地址转Base64数据

最近做一个项目，但是目前服务器还不能存储图片。说要把图片存到本地，但是如果给的是网络图片地址还好可以直接加载，但是现在要求把拍照或者图库的照片存到本地。如果直接存储那个路径肯定是不可用的，所以转成了Base64存储起来。如果有其他更好的方式欢迎各位大佬留言哦~

//选择图片
function chooseEvent() {
  uni.chooseImage({
    count:1, // 默认9
    sizeType: ['original', 'compressed'], // 可以指定是原图还是压缩图，默认二者都有
    sourceType: ['camera', 'album'], // 可以指定来源是相册还是相机，默认二者都有
    success: function (source) {
      if(!source.tempFiles) return
      for (let i = 0; i < source.tempFiles.length; i++) {
		   pathToBase64(source.tempFiles[i].path).then(res=>{
			    shoeImgUrl.value = res
		   }) 
      }
    }

  });
}

//路径转Base64
function pathToBase64(path) {
    return new Promise(function(resolve, reject) {
        if (typeof window === 'object' && 'document' in window) { //判断当前是否是浏览器
            if (typeof FileReader === 'function') {
                var xhr = new XMLHttpRequest()
                xhr.open('GET', path, true)
                xhr.responseType = 'blob'
                xhr.onload = function() {
                    if (this.status === 200) {
                        let fileReader = new FileReader()
                        fileReader.onload = function(e) {
                            resolve(e.target.result)
                        }
                        fileReader.onerror = reject
                        fileReader.readAsDataURL(this.response)
                    }
                }
                xhr.onerror = reject
                xhr.send()
                return
            }
            var canvas = document.createElement('canvas')
            var c2x = canvas.getContext('2d')
            var img = new Image
            img.onload = function() {
                canvas.width = img.width
                canvas.height = img.height
                c2x.drawImage(img, 0, 0)
                resolve(canvas.toDataURL())
                canvas.height = canvas.width = 0
            }
            img.onerror = reject
            img.src = path
            return
        }
        if (typeof plus === 'object') { //判断当前是否是App等原生平台
            plus.io.resolveLocalFileSystemURL(getLocalFilePath(path), function(entry) {
                entry.file(function(file) {
                    var fileReader = new plus.io.FileReader()
                    fileReader.onload = function(data) {
                        resolve(data.target.result)
                    }
                    fileReader.onerror = function(error) {
                        reject(error)
                    }
                    fileReader.readAsDataURL(file)
                }, function(error) {
                    reject(error)
                })
            }, function(error) {
                reject(error)
            })
            return
        }
        if (typeof wx === 'object' && wx.canIUse('getFileSystemManager')) {//判断当前是否是微信小程序
            wx.getFileSystemManager().readFile({
                filePath: path,
                encoding: 'base64',
                success: function(res) {
                    resolve('data:image/png;base64,' + res.data)
                },
                fail: function(error) {
                    reject(error)
                }
            })
            return
        }
        reject(new Error('not support'))
    })
}

//处理文件路径
function getLocalFilePath(path) {
    if (path.indexOf('_www') === 0 || path.indexOf('_doc') === 0 || path.indexOf('_documents') === 0 || path.indexOf('_downloads') === 0) {
        return path
    }
    if (path.indexOf('file://') === 0) {
        return path
    }
    if (path.indexOf('/storage/emulated/0/') === 0) {
        return path
    }
    if (path.indexOf('/') === 0) {
        var localFilePath = plus.io.convertAbsoluteFileSystem(path)
        if (localFilePath !== path) {
            return localFilePath
        } else {
            path = path.substr(1)
        }
    }
    return '_www/' + path
}

/* base64转文件路径 */
function base64ToPath(base64){
	    return new Promise(function(resolve, reject) {
	        if (typeof window === 'object' && 'document' in window) {
	            base64 = base64.split(',')
	            var type = base64[0].match(/:(.*?);/)[1]
	            var str = atob(base64[1])
	            var n = str.length
	            var array = new Uint8Array(n)
	            while (n--) {
	                array[n] = str.charCodeAt(n)
	            }
	            resolve((window.URL || window.webkitURL).createObjectURL(new Blob([array], { type: type })))
							return
					}
	        var extName = base64.match(/data\:\S+\/(\S+);/)
	        if (extName) {
	            extName = extName[1]
	        } else {
	            reject(new Error('base64 error'))
	        }
	        var fileName = Date.now() + '.' + extName
	        if (typeof plus === 'object') {
						debugger
	            var bitmap = new plus.nativeObj.Bitmap('bitmap' + Date.now())
	            bitmap.loadBase64Data(base64, function() {
	                var filePath = '_doc/uniapp_temp/' + fileName
	                bitmap.save(filePath, {}, function() {
	                    bitmap.clear()
	                    resolve(filePath)
	                }, function(error) {
	                    bitmap.clear()
	                    reject(error)
	                })
	            }, function(error) {
	                bitmap.clear()
	                reject(error)
	            })
	            return
	        }
	        if (typeof wx === 'object' && wx.canIUse('getFileSystemManager')) {
	            var filePath = wx.env.USER_DATA_PATH + '/' + fileName
	            wx.getFileSystemManager().writeFile({
	                filePath: filePath,
	                data: base64.replace(/^data:\S+\/\S+;base64,/, ''),
	                encoding: 'base64',
	                success: function() {
	                    resolve(filePath)
	                },
	                fail: function(error) {
	                    reject(error)
	                }
	            })
	            return
	        }
	        reject(new Error('not support'))
	    })
	}